The present invention relates to a printer having a lid for covering a print head and a platen confronting the print head, in which the lid is openably hinged to a printer housing. More particularly, the invention relates to such a printer having a means for controlling printer operation when a printing process is to be resumed after the lid has been opened.
Printers generally include a lid for covering a print mechanism including a print head and a platen, in which the lid is openably hinged to a printer housing. The printer lid is not normally opened during printing operation, however, it needs to be opened when a paper jam has occurred or an ink ribbon is to be replaced. Since the uncovered print mechanism is dangerous to the operator, conventional printers have a mechanism for interrupting the printing operation when the lid is opened during operation. When removing the jammed paper or replacing the ink ribbon, the print head and its carriage may be touched and moved by the operator. The conventional printers have a mechanism for correcting the position of the carriage before the printing process is resumed after the lid has been opened.
However, such conventional printers have the following disadvantage. To resume the printing process, the lid is closed, and an on-line/off-line selector key is pressed to select an on-line mode. Even if the carriage or surrounding parts are touched by the operator during printer shutdown, the print position can be corrected since the carriage can be positionally corrected as described above. However, if the spacing between the print head and the sheet of print paper set on the platen is varied due to the touch to the carriage by the operator, then the quality of the printed letters may be lowered since such spacing is not corrected in the conventional printers.
Accordingly, the conventional printers may cause printing irregularity once the lid is opened during printer operation.